<template>
	<div>
		<router-link
		  tag="div"
		  to="/"
		  class="header-abs"
		  v-show="showAbs"
		 >
			<div class="iconfont header-abs-back">&#xe624;</div>
		</router-link>
		<div
		  class="header-fixed"
		  v-show="!showAbs"
		  :style='opacityStyle'
		>
			<router-link to="/">
				<div class="iconfont header-fixed-back">&#xe624;</div>
			</router-link>
			景点详情
		</div>
	</div>
</template>

<script>
	export default {
		name: 'DetailHeader',
		data () {
			return {
				showAbs: true,
				opacityStyle: {
					opacity: 0
				}
			}
		},
		methods: {
			handleScroll () {
				const top = document.documentElement.scrollTop
				if (top >60 ) {
					let opacity = top/140
					opacity = opacity >1 ? 1 :opacity
					this.opacityStyle = {opacity}
					this.showAbs = false
				} else {
					this.showAbs = true
				}
			}
		},
		activated () {
			window.addEventListener('scroll',this.handleScroll)
		},
		deactivated () {
			window.removeEventListener('scroll',this.handleScroll) 
		}
	}
</script>

<style lang="stylus" scoped>
	@import '~styles/varibles.styl'
	.header-abs
		position: absolute
		left: .2rem
		top: .2rem
		width: .8rem
		height: .8rem
		line-height: .8rem
		border-radius: .4rem
		text-align: center
		background: rgba(0,0,0,.8)
	.header-abs-back
		color: #fff
		font-size: .4rem
	.header-fixed
		z-index: 2
		position:fixed
		top: 0
		left: 0
		right: 0
		height: $headerHeight
		line-height: $headerHeight
		text-align: center
		color: #fff
		background: $bgColor
		font-size: .32rem
	.header-fixed-back
		position: absolute
		left: 0
		top: 0
		width: .64rem
		text-align: center
		font-size: .4rem
		color: #fff
</style>
